<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div style="width: 500px; background-color: yellow">
        <div style="width: 20%; float: left; background-color: blue">1234</div>
        <div style="width: 50%; float: left; background-color: green">2345</div>
        <div style="width: 10%; float: right; background-color: red">3456</div>
        <div style="clear: both"></div>
    </div>
</body>
</html>